In this paper, we investigate the performance of wireless ad hoc networks with traffic loads beyond saturation. While it is desirable to operate a network below saturation, an ad hoc network should be designed to degrade its performance gracefully under severe loads. Using AODV (ad hoc on-demand distance vector) and 802.11 as example routing and MAC (Medium Access Control) level protocols, we show that the throughput of an ad hoc network drops off rapidly beyond saturation. The reasons for this behavior are high route maintenance overhead and increased radio interference. We propose modifications to the protocols to mitigate these negative factors and provide graceful degradation of performance under heavy loads.
Saman Desilva, Rajendra V. Boppana